The management of complicated networks such as telecommunications networks or sophisticated computer networks is tremendously expensive. A substantial portion of this cost arises from incomplete, incorrect or ambiguous knowledge about a network. For example, a telecommunications network operator may not have an accurate record of how network switches are configured, leading to failed attempts to fix problems or provision new services. This lack of knowledge can in some instances be remedied by polling the networking equipment to determine its actual settings.
However, a more fundamental ambiguity arises at the physical level of network cable management. Network cables may be added, removed or moved by support personnel for a variety of reasons, often to solve urgent problems. However, it is very difficult to maintain an accurate record of exactly which cable is connected to which port of a given piece of equipment (e.g., a patch panel of a telecommunications switch), since the cables may so easily be connected, disconnected, and reconnected.
Typically, network cable locations and connections are tracked manually, by, for example, putting printed tags on each cable, storing the tag-to-cable mappings in a database, and then attempting to manually keep the database up to date. In addition, physical inventories of network offices, in which the cables are identified, tagged and mapped, are themselves typically performed manually. In a large telecommunications or computer network system, it is an extremely expensive proposition to keep track of every cable, where it is, where it runs, and which port on a given piece of equipment it is plugged into. As a result, equipment inventory databases are notoriously inaccurate, and the negative results include, inter alia, loss of network capacity, increased service times and a much greater chance of disruptive service errors. Thus, it would be highly advantageous if there were an automated mechanism able to identify the connections between cables and equipment ports of a given piece of equipment such as, for example, a patch panel of a telecommunications switch.
One approach is to use Radio Frequency Identification (RFID) systems for the automatic determination of cable connections, by employing RFID tags on both cable ends and equipment ports, determining each of their respective locations (with use of one or more RFID sensing devices), and then determining the physical proximity therebetween. Based on this determined physical proximity, juxtaposition (e.g., a connection) between the cable and the port can be determined. This approach is described in detail in U.S. Pat. No. 6,847,856, “Method For Determining Juxtaposition Of Physical Components With Use of RFID Tags” by Philip L. Bohannon, issued Jan. 25, 2005 and commonly assigned to the assignee of the present invention. U.S. Pat. No. 6,847,856 is hereby incorporated by reference as if fully set forth herein.
Another approach to the use of Radio Frequency Identification (RFID) systems for the automatic determination of cable connections might comprise the use of RFID tags on each cable end and a single, independent receiver (e.g., antenna) at (or near to) each device port. Then, the specific cable end that is connected to each device port (if any) can be advantageously determined by merely reading the ID value of the connected cable end. This, however, might be prohibitively expensive. (As is familiar to those of ordinary skill in the art, whereas RFID tags are extremely inexpensive, RFID readers are typically not so inexpensive.)
A better approach is to use an RF antenna grid, employed on a device having a plurality of device ports (e.g., cable end connection points), which may, for example, be physically organized in a two-dimensional rectangular arrangement. (As used herein, a “device port” is any physical receptacle into which an end of a cable may be connected. The receptacle and cable may, for example, be adapted to carry electrical or optical signals, but they are not necessarily limited thereto. Also as used herein, the term “antenna grid” is not meant to imply any particular arrangement of antennas or device ports to which it is employed, but rather represents any antenna arrangement in which either multiple device ports are associated with a given RFID antenna and/or in which two or more distinct antennas are associated with a given device port.) In particular, each of the RFID antennas may be advantageously located on the device such that it is in close physical proximity to each of two or more device ports. (As used herein, the term “close physical proximity” between an RFID antenna and a device port is defined by the ability of the RFID antenna to sense the presence of an RFID tag attached to a cable end which has been plugged into the device port when directed to do so by an RFID reader.)
This is the approach employed in co-pending U.S. patent application Ser. No. 10/812,598, “Method And Apparatus For The Automatic Determination Of Network Cable Connections Using RFID Tags And An Antenna Grid,” filed on Mar. 30, 2004 by Clifford E. Martin (hereinafter, “Martin”) and commonly assigned to the assignee of the present invention. In particular, Martin discloses a method and apparatus whereby an RF antenna grid is advantageously employed on a device (e.g., a patch panel) having a plurality of device ports (e.g., cable connection points) which may, for example, be physically organized in a two-dimensional rectangular arrangement. Then, when RFID tags have been fixed to one or more cable ends, it can advantageously be determined which of the one or more cables are connected to which of the device ports on the patch panel. The RF antenna grid may comprise a plurality of individual antennas which are advantageously multiplexed such that a single RFID reader can handle the sensing for all antennas. U.S. patent application Ser. No. 10/812,598 is hereby incorporated by reference as if fully set forth herein.
Although the RF antenna grid design described in Martin solves the problem of automatically determining network connections, that approach cannot be easily employed with respect to existing patch panel systems used in current telecommunications networks without disrupting network operations. In particular, such a design may require the forklift replacement of existing patch panels with electronic switches or proprietary patch panels. Such an approach, which requires a retrofitting of major telecommunications equipment components can prove to be quite costly.